Story URL: http://news.medill.northwestern.edu/chicago/news.aspx?id=111615
Story Retrieval Date: 5/18/2013 1:05:53 PM CST
Conservationists commonly rely on radio telemetry to find animals in the wild and observe them in their natural habitats. To track animals using this technique, researchers first use a special glue to affix a small transmitter to an individual animal. The transmitter emits a signal on a unique frequency, which researchers record for each animal.
For mammals, the transmitter should be no more than 5 percent of the total body weight. Birds, however, have a more delicate center of gravity during flight, so experts say they should carry less than 3 percent of their total body weight, according to the Chicago-based Wildlife Materials Inc.
Out in the field, a researcher will set the hand-held receiver to the specific signal of the desired animal and use an antennae to search a broader distance around themselves. The receiver then searches for the signal, which beeps louder as the researcher gets closer to the transmitter.
Dan Thompson, an ecologist with the DuPage Forest Preserve, likens the process to the children’s game of hot and cold—the “warmer” you are to the animal you are tracking, the louder the signal will be.
Satellite tracking enables researchers to follow animals that travel great distances. According to Thompson, it is a better option than radio for following animals that will leave the local area such as birds, which fly elsewhere for winter. However, he notes, though satellite offers a lot of data, “you don’t want to just rely on data points.”
Radio telemetry forces researchers into the field, where they can witness how an animal is actually using its ecosystem.
Most Chicagoans are eagerly awaiting spring as temperatures dip to their lowest in years. If it's possible, local researchers may be even more fervent as they wait for the Blanding’s turtles they have been tracking in preserved Chicago wetlands to come out from hibernation.
Native to the Great Lakes region, Blanding’s turtles are listed as threatened in the state, meaning they are declining so quickly that they are at risk for becoming endangered.
Conservationists note that, because this species serves as a barometer for the health of the local environment, its decline is a serious problem.
In October, researchers at the Peggy Notebaert Nature Museum in Chicago released into the wild three two-year-old turtles and roughly 100 hatchlings, which quickly went into hibernation. “This spring, we will go back out and start trying to track them in the same area” to learn more about their behaviors and risks, said Celeste Troon, manager of living vertebrates at the Peggy Notebaert Nature Museum.
Conducted in collaboration with the DuPage Forest District and the Willowbrook Wildlife Center, the process is called “headstarting,” meaning scientists raise turtle hatchlings for roughly two years before releasing them. Ecologists note this helps them grow stronger and two- to three- times larger than they would alone in the wild.
The species’ importance stretches beyond its stature as “the local representative” for wildlife, according to Troon. Specifically, the drop in the turtle’s population is “indicative of the loss of wetlands,” she said.
“Wetlands do a great deal of good in filtering out pollutants before they reach our water system,” she said, adding that the turtle’s population is declining because wetlands are being drained as urbanization increases. “By preserving their habitat and therefore [the turtles], we are preserving ourselves, too.”
Human causes, human fixes
The turtle’s decline across roughly the past two decades has been gradual. Yet, from an ecological standpoint, “whenever an individual species is starting to struggle, it’s a sign of concern,” said Dan Thompson, an ecologist with the DuPage Forest Preserve.
Because they live in a variety of habitats including marshes, creeks, and the edges of lakes and ponds, researchers say the turtles, known for their long necks and bright yellow throats, are vulnerable to threats from both humans and predators.
Extinction is definitely a natural process, but “when environments start to degrade and populations begin to struggle in relatively short periods of time, it usually indicates an association with human stresses,” Thompson said.
Most significantly, land development for suburban towns and farming has depleted much of these turtles’ natural habitat, as wetlands are drained and new roads are put in.
“These are things you definitely want to try to correct when you can,” he noted, adding that pressures put on the Blanding’s turtle can be directly related to human activities. “We’ve created a problem, so it’s really up to us to come up with a solution and try to correct it.”
One path to a solution involves using radio telemetry [see sidebar] to study the turtles in their natural habitats. To do this, researchers attach a radio transmitter to the side of a turtle shell before putting it back in the wild. Then, using radio receiver equipment, researchers can go into the field, find the exact turtle and record its behavior and location.
What individuals can do to help
Chicagoans can contribute to the solution, as well. According to Whitney Banning, a doctoral candidate working with the Illinois Natural History Survey, Blanding’s turtles are not pets. “If you see a turtle, especially a Blanding’s, leave it alone. Don’t pick it up and bring it home,” she said. To help researchers, people also can take photos and report the sighting, she added.
One of the greatest mortality threats for turtles in the Chicago area is getting run over, researchers said. Female Blanding’s turtles travel miles to find suitable nesting grounds and thus often cross roads, so drivers should keep a watchful eye on the road, according to Troon.
People also can protect turtles by securing their garbage. This keeps nighttime raiders including coyotes and raccoons, which feed on turtle eggs and hatchlings, from “proliferating any more than they already have,” Troon said.
Lastly, general conservation remains an important part of protecting the turtles and the local environment. “The more [people] that get involved in conservation, preservation and restoration, the more areas [the turtles] will have to live in,” Troon said.
Thompson agrees. “This is just one example of many species that are out there struggling, endangered and or threatened, and society as a whole needs to really understand and address this,” he said.
“If we can make this a priority then we have a great opportunity to hopefully correct a lot of these issues.” Thompson warned, however, that if conservation remains less of a priority, the future for many species is in danger.